On the Ihermochemistry of the Nd-Al Alloys

The formation heats of the intermetallic compounds of aluminium with neodymium were measured using a direct isoperibol differential calorimeter. The composition and equilibrium state of the samples were checked by metallographic and X-ray analyses. The values of Δ f H (kJ/mol of atoms) for the following compounds were obtained for the reaction in the solid state at 300 K: Nd 3 Al:- 27.5±2, Nd 2 Al:-36.5±2, NdAl:-50.0±2, NdAl 2 :-53.0±2, NdAl 3 :-45.0±2, Nd 3 Al 11 :-41.0±2. The results are discussed and compared with those of other similar rare earth-aluminium compounds